Sima is heavier than sial primarily due to its higher density, which stems from its composition. Sima is richer in heavier elements.
Composition and Density
- Sima: This layer is primarily composed of silicates of magnesium and iron, often referred to as mafic rocks. These elements are relatively dense, giving sima a higher density. According to the reference, Sima has a density between 2800-3300 kg/m3, which is significantly higher than that of sial.
- Sial: In contrast, sial is composed mostly of silicates of aluminum, hence "si-al." Aluminum is a lighter element than iron and magnesium, resulting in a lower overall density.
| Feature | Sima | Sial |
|---|---|---|
| Primary Elements | Iron and Magnesium | Aluminum |
| Density | 2800-3300 kg/m3 | Lower than Sima |
| Rock Type | Mafic (e.g., basalt, gabbro) | Felsic (e.g., granite) |
Explanation of Density Differences
The key reason for the density difference is the presence of a higher concentration of iron and magnesium in sima, as stated in the provided reference. These heavy elements contribute more to mass within a given volume, thus increasing its density and making sima heavier than sial.
- Iron and Magnesium: These elements are heavier than the aluminum that is abundant in sial.
- Density and Weight: Since density is mass per unit volume, a material with a higher density will weigh more for the same volume.
Summary
The higher density, driven by the presence of iron and magnesium, is the main reason why sima is significantly heavier than sial. The reference provides the range of densities for sima and hints at that the density of sial is lower.
